One common area of computer fraud involves attempts by organizations to infiltrate and compromise computers of ordinary people, and by that action to elicit confidential information or manipulate otherwise legitimate transactions. Various forms of malware are programmed to facilitate these fraudulent actions, for example, by analyzing sensitive information from textual content of webpages and other documents on client computing devices. To determine the content of a webpage, malware can identify strings of text that are arranged for display on the page. Characters in the strings of text may be encoded according to certain standards that assign unique numeric values to characters (e.g., the common ASCII character set or the newer Unicode character set), and these values can be understood across multiple computing platforms that execute the webpage so that the characters may be properly processed and displayed according to their original meaning.